It is common practice today to employ a ribbon cassette carrying an endless ribbon as an ink source for typewriters and computer driven printers, the latter typically being of either the dot matrix or printwheel type. One method of storing such a ribbon has been randomly stuffing it into a chamber of a cassette. This often results in an extremely high number of bends or creases in the ribbon, this occurring at repeated distances on the order of one-quarter inch or less. Thus, with a typical 360-inch length ribbon, there may be on the order of 1,440 bends or creases. It is to be appeciated that this has two distinct disadvantages. One is that an impact of a print head through a crinkled ribbon will produce uneven print. The second disadvantage is that each bend or crease in a ribbon consumes extra storage space and thus the storage capacity for ribbon is diminished.
Another method of storing such ribbon in a cassette is by directing the ribbon into a storage cavity where it is stored in orderly arranged folds. Typically, the ribbon is routed through adjacent feed rollers or drive wheels which grip the ribbon therebetween and direct the ribbon into a storage compartment in the casette where it is stored in folded relation.
In addition to the employment of devices for directing a ribbon into a storage compartment of a cassette, certain cassettes are configured to direct ribbon across the print head of the printer along a line which is at a small angle, for example, 2.degree., with the base line of printing of a print head. The reason for this is that there is less tendency for repetitive striking of an area of a ribbon by a print head and thus less wear on the ribbon. This in turn enables a greater number of cycles of use of a given length of ribbon. In the patent to David W. Bell et al., U.S. Pat. No. 4,209,261, issued June 24, 1980, this offset has been accomplished by an intentional angular misalignment between a drive shaft of the host printer and the drive roller assembly of the cassette. In order to accomplish this intentional offset and still allow the ribbon to pass through adjacent drive wheels of the angled roller assembly, the storage compartment is angled between the extreme sides or edges of the cassette body. The storage compartment and ribbon path are disposed in generally parallel relation. While the difference in elevation of the ribbon path at the entrance and exit of the storage compartment has been achieved so that the ribbon is directed across the print head of the printer at an oblique angle with the base line of the print head, the resulting intentional misalignment between the drive roller assembly of the cassette and the drive shaft of the printer may result in undue binding and thus undue wear on both the printer and cassette.
It is the object of this invention to overcome the aforesaid disadvantages and to provide a ribbon cassette which effects an ordered storing of the ribbon with substantially fewer number of bends while eliminating the problem of misalignment between the drive member of the printer and a drive roller of the cassette.